Washable pillow

ABSTRACT

A washable pillow includes a quilted sleeve comprising a viscoelastic foam layer and a till material that can comprise viscoelastic foam. the pillow may be washed and dried using conventional household methods without damage or lass of mechanical properties.

FIELD OF THE INVENTION

The present application generally relates to pillows and cushions, andmore particularly to a washable pillow or cushion containingviscoelastic foam,

BACKGROUND OF THE INVENTION

The neck of a person lying in a supine or side-lying position is oftenout of alignment with the person's spine. That is commonly the case whenthe person's neck is supported by a pillow or multiple pillows such thatthe neck lies at an angle defined by the deflected height of thepillow(s), wherein the angle is typically not co-planar with the spine.The deflected height of the pillow is closely related to the stiffnessimparted by its constituent materials. Pillows containing viscoelasticfoam may be used to encourage proper neck alignment.

Although pillows constructed at least in part with viscoelastic foamhave many desirable properties, many viscoelastic foams have propertiesthat can generate design challenges. For example, some viscoelasticfoams have less durability and/or are weaker (e.g., tear strength,tensile strength, and the like) than other types of foam. As anotherexample, some viscoelastic foams retain large quantities of water, andcan be difficult to dry. In light of these properties, improvementsregarding the use of viscoelastic foam in pillows and cushions continueto be welcome additions to the art.

SUMMARY OF THE INVENTION

Some embodiments of the present invention provide a pillow containingmultiple viscoelastic foam components that are able to withstandrepeated washing and drying with conventional detergents and laundrymachines without damage or loss of mechanical properties.

The present invention provides, in one aspect, a washable pillowcomprising a sleeve defining a cavity and a filler material positionedwithin the cavity. The sleeve and/or filler material includes aviscoelastic foam having a hydrophobicity expressed in terms of wateruptake between about 0% (w/w) and about 5% (w/w), an average cell sizebetween about 0.16 mm and about 0.19 mm, and an air permeability betweenabout 1.0 liters per second and about 5.0 liters per second.

The present invention provides, in another aspect, a washable pillowcomprising a sleeve that includes a first panel and a second panelconnected to the first panel along the edges of the panels to form acavity between the panels, and a filler material positioned within thecavity. The sleeve and/or filler material includes a viscoelastic foamthat in some cases has a hydrophobicity expressed in terms of wateruptake between about 0% (w/w) and about 5% (w/w). Stitching extendsthrough each of the first and second panels to define a quilting patternbetween the edges of the connected panels. In addition, each of thefirst and second panels can include a viscoelastic foam layer, a firstfabric layer (e.g., of netting material, in some embodiments) adjacentan interior surface of the viscoelastic foam layer, and a second fabriclayer adjacent an exterior surface of the viscoelastic foam layer.

Other features and aspects of the invention will become apparent byconsideration of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a pillow representing anexemplary embodiment of the invention.

FIG. 2 is an assembled, partial cross-sectional view of the pillow ofFIG. 1 through section 2-2 in FIG. 4.

FIG. 3 is an exploded perspective view of a portion of the pillow ofFIG. 1.

FIG. 4 is an assembled plan view of the pillow of FIG. 1.

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the accompanyingdrawings. The invention is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

The disclosed pillow includes viscoelastic foam, sometimes referred toas “memory foam” or “low resilience foam.” Viscoelastic foam can havevarying degrees of density, pressure responsiveness, porosity, thermalconductivity, thermal diffusity, etc, However, viscoelastic foam istypically characterized by slow recovery and low resilience. The use ofviscoelastic foam permits the pillow to conform to the shape of theportion of a person's body that contacts the pillow. While conventionalmaterials typically exhibit constant stiffness or hardness in responseto changing temperatures, the stiffness or hardness of viscoelastic foamis often temperature dependent, and in many cases is temperaturedependent based upon body heat of a user (having a lower stiffness orhardness at an elevated temperature as compared to its stiffness at acooler temperature). The body heat of a user acts to soften the portionof the pillow in contact with the body, while the portion of the pillownot contacting the body remains more firm. As a result, the disclosedpillow allows for greater comfort over conventional pillows byaccommodating each user's body form.

In general, viscoelastic foam materials cannot be nondestructivelywashed and dried. For example, most viscoelastic polyurethane foams aresubstantially hydrophilic, and as a result tend to absorb and retainliquid and exhibit swelling when washed or otherwise exposed to water.Hydrophilicity and limited air permeability in typical viscoelasticfoams makes complete drying difficult In addition, the tensile strengthof such foams often decreases when wet, leading to fragility andfrequent distortion, cracking, breaking, or fragmentation of the foamstructure and loss of viscoelastic properties upon exposure to themechanical stresses associated with typical washing and dryingprocedures. As a result, washing is generally not recommended forconventional viscoelastic foam pillows.

FIGS. 1 and 2 illustrate a washable pillow 10 having a quilted,multi-layered sleeve 14 and viscoelastic foam filler material 34 withina cavity 12 of the sleeve 14. With reference to FIGS. 2 and 3, thesleeve 14 includes opposed layers of viscoelastic, foam 18. In someembodiments, the viscoelastic foam layers 18 of the sleeve 14 have adensity of about 65 kg/m³. However, a suitable density for theviscoelastic foam layers 18 for an average weight pillow (for example)can be between about 30 and about 140 kg/m³, and in some embodimentsbetween about 40 and about 100 kg/m³, and in other embodiments betweenabout 45 and about 80 kg/m³, and especially between about 50 and about70 kg/m³. Further, a suitable density for the viscoelastic foam layers18 for a lightweight pillow (again, by way of example) can be less thanabout 50 kg/m³. Likewise, a suitable density for the viscoelastic foamlayers 18 for a heavyweight pillow, for example, can be greater thanabout 110 kg/m³, Alternatively, the viscoelastic foam layers 18 can haveany density in accordance with the desired characteristics of the pillow10.

The hardness of the viscoelastic foam layers 18 used in the sleeve 14and of the viscoelastic foam used in the filler material 34 may bebetween about 30 N and about 70 N, and in some embodiments between about35 N and about 60 N, and in other embodiments between about 37 N andabout 55 N. The overall stiffness or hardness of the pillow 10 isassociated with the stiffness of the individual viscoelastic foam layers18 and the filler material 34. As such, the overall stiffness orhardness of the pillow 10 may be affected by varying the stiffness ofthe individual viscoelastic foam layers 18 and/or the filler material34.

The viscoelastic foam layers 18 of the sleeve 14 are, in someembodiments, about 10 mm thick and can have thermally-responsiveproperties as described above. The viscoelastic foam of the fillermaterial 34 can have similar thermal thermally-responsive properties. Asuitable thickness for the viscoelastic foam layers 18 for an averageweight pillow, for example, can be between about 5 mm and 15 mm.However, a suitable thickness for the viscoelastic foam layers 18 for alightweight pillow, for example, can be less than about 7 mm. Further, asuitable thickness for the viscoelastic foam layers 18 for a heavyweightpillow, for example, can be greater than about 13 mm. The viscoelasticfoam layers 18 are made from a washable viscoelastic polyurethane foammaterial as will be further described.

As shown in FIGS. 1-3, the sleeve 14 also includes a fabric layer 22covering the outside surface of each viscoelastic foam layer 18 and afabric layer 26 covering the inside surface of each viscoelastic foamlayer 18. In some embodiments (e.g., the illustrated embodiment), thefabric layer 26 covering the inside surface of each viscoelastic foamlayer 18 is a netting layer, although other types of fabric can beinstead be used. Accordingly, reference to a “netting” fabric layer forthe inside surface of the viscoelastic foam layers 18 is made hereinonly by way of example. In some embodiments, a first viscoelastic foamlayer 18 a is sewn together with a first fabric layer 22 a and a firstnetting layer 26 a, respectively, covering opposing sides of the firstviscoelastic foam layer 18 a to form a first layered panel 28 a (FIGS. 1and 2). Similarly, a second viscoelastic foam layer 18 b is sewntogether with a second fabric layer 22 b and a second netting layer 26 bcovering opposing sides of the second viscoelastic foam layer 18 b toform a second layered panel 28 b. For example, fabric and netting layers22, 26 may be stitched to a viscoelastic foam layer 18 along their edges(e.g., with stitches extending fully through the fabric and nettinglayers 22, 26 and the viscoelastic foam layer 18). In addition, thelayers of each panel 28 may be quilted together across the face of eachpanel 28, that is, between the edges of the connected layers 18, 22, 26(again, with stitching 30 (FIG. 3) that extends through and joins allthree layers 18, 22, 26) and that may define a quilting pattern. Anexemplary quilting pattern is shown in FIG. 4. In the illustratedembodiment, stitching 30 assumes a waveform pattern having a wavelengthA, a maximum distance 13 between adjacent waveforms, and a minimumdistance C between adjacent waveforms. In some embodiments, thewavelength A may be between about 20 and 30 centimeters, and in otherembodiments may be about 26 centimeters. In some embodiments, themaximum distance B between adjacent waveforms may be between about 5 and15 centimeters, and in other embodiments may be about 12 centimeters, Insome embodiments, the minimum distance C between adjacent waveforms maybe between about 1 and 10 centimeters, and in other embodiments may beabout 3 centimeters. Any other quilting pattern can be used across theface of each panel 28, such as, for example, rectangular, square,circular, linear, rope, zigzag, crosshatch, swirl, and starburstpatterns.

With continued reference to FIG. 3, the fabric layers 22 and nettinglayers 26 may serve to anchor the stitches 30 that secure the fabric,netting, and viscoelastic foam layers 22, 26, 18 of the panels 28together. Without the reinforcing fabric and netting layers 22, 26, theless durable viscoelastic foam layers 18 would have to anchor thestitches 30 directly. Anchoring stiches 30 in the viscoelastic foamlayers 18 could result in tearing of the foam near the stitches 30 as aresult of normal use of the pillow 10. Therefore, the reinforcing fabricand netting layers 22, 26 provide a measure of durability to the pillow10. In addition, quilting through the three layers 18, 22, 26 along theedges and/or across the face of each panel 28 provides additionalmechanical reinforcement that protects the viscoelastic foam layer 18 ofeach panel 28 from cracking or tearing when washed and dried. In someembodiments, the quilt stitching length may be about 2.5 stitches percentimeter and may use core spun thread for added strength. The fabricand netting layers 22, 26 are, in some embodiments, made from durablematerials, such as cotton, polyester, a cotton/polyester blend, and soforth. In other embodiments, the netting layer 26 is made from apolyester single jersey material.

During manufacture, first and second layered panels 28 a, 28 b are sewntogether to form the sleeve 14 with an open end, whereby the nettinglayers 26 comprise the inner layers of the sleeve 14 facing the cavity12, and the fabric layers 22 comprise the outer layers of the sleeve 14.The filler material 34 is then inserted through the open end of thesleeve 14 until the desired amount of filler material is positionedwithin the sleeve. The open end of the sleeve 14 is then sewn closed(FIG. 2), thereby encasing the filler material 34 within the sleeve 14and defining the pillow 10.

With reference to FIG. 1, the pillow 10 may then be inserted within acover 36. The cover 36 surrounds and encases the pillow 10 and conformsto the shape of the pillow 10. The cover 36, in some embodiments, ismade from a durable and washable fabric material, such as acotton/polyester blend. As shown in FIG. 1, a slot 40 extends across thecover 36 along the cover's edge. The pillow 10 may be inserted into thecover 36 through the slot 40. The pillow 10 may also be removed from thecover 36 through the slot 40 to facilitate cleaning of the cover 36. Theslot 40 is resealable to close the cover 36 around the pillow 10 and toopen the cover 36 for removing the pillow 10. A closure device 44 isused to open and close the slot 40. In the illustrated embodiment, theclosure device 44 is a zipper, although the closure device 44 couldalternatively comprise snaps, buttons, hook and loop fastener material,overlapping flaps, laces, or other suitable fasteners.

A suitable density for the viscoelastic foam filler material 34 for anaverage weight pillow, for example, can be between about 30 and about140 kg/m³. In some embodiments of the present invention, the fillermaterial 34 is granulated, or shredded, viscoelastic foam having adensity of about 65 kg/m′ for a firmer-feel pillow. A suitable densityfor granulated viscoelastic foam filler material 34 for relativelylightweight pillow having a relatively soft feel, for example, can beabout 45 kg/m³. In another embodiment, a medium-weight pillow having amedium feel can be produced using a 1:1 mixture of granulatedviscoelastic foam having densities of about 65 kg/m³and about 45 kg/m³.Alternatively, the granulated viscoelastic foam utilized as the fillermaterial 34 can have any density in accordance with the desiredcharacteristics of the pillow 10.

In addition, a viscoelastic foam filler material 34 may in someembodiments possesses an indentation load deflection, or “ILD,” of 65%between 100-500 N loading, and a maximum 10% rebound according to thetest procedure governed by the ASTM-D-1564 standard.

The granulated filler material 34 can be made up of recycled, virgin, orscrap viscoelastic material. The granulated filler material 34 mayconsist of pieces of a nominal length, or the granulated filler material34 may consist of pieces of varying lengths. For example, granulatedfiller material 34 may have a nominal length of about 1.3 cm. Also,granulated filler material 34 may consist of varying lengths betweenabout 0.6 cm and about 2 cm. The granulated filler material 34 can be asshort as 0.3 cm and as long as 4 cm, or the filler material 34 can beany length in accordance with the desired characteristics of the pillow10. In some embodiments, the granulated filler material 34 is comprisedof 16-20% having a length longer than 2 cm, 38-42% having a lengthbetween 1 and 2 cm, and 38-42% of the pieces shorter than 1 cm.Significant cost savings and waste reduction can be realized by usingscrap or recycled filler material rather than virgin filler material.

The viscoelastic foam used for the sleeve 14 and the filler material 34may be made from a polyurethane foam material. The viscoelastic foam(s)can be selected for responsiveness to any range of temperatures.However, in some embodiments, temperature responsiveness in a range of auser's body temperatures (or in a range of temperatures to which thepillow 10 is exposed by proximity to a user's body resting thereon) canprovide advantages. As used herein, a viscoelastic foam is considered“responsive” to temperature changes if the viscoelastic foam exhibits achange in hardness of at least 10% measured by ISO Standard 3386 throughthe range of temperatures between 10 and 30 degrees Celsius.

The viscoelastic foams used for the sleeve 14 and filler material 34 mayexhibit substantial hydrophobicity, which limits swelling and waterabsorption during washing, and facilitates drying of the pillow 10.Numerous methods may be used to measure the hydrophobicity of amaterial. For example, hydrophobicity can be assessed by measuring hecontact angle between the surface of a product and the edge of a waterdroplet deposited on the surface of the product. In general, a highercontact angle indicates greater hydrophobicity. Another common methodfor measuring hydrophobicity uses standard water ratings, which tests amaterial for absorption of liquid droplets containing water and anincreasing proportion of isopropanol. In the standard rating scale, W0corresponds to 100% water, and W10 corresponds to 100% isopropanol. Eachincremental increase in the proportion of isopropanol lowers thecohesive properties within the droplet and therefore makes the dropletmore susceptible to being absorbed into the material. Another method formeasuring hydrophobicity involves measuring water uptake of a product.An article may be washed in a commercially available washing machine,for example, at a water temperature of 60 degrees Celsius. The articleis then dried for two hours in a commercially available tumble dryer andsubsequently allowed to rest for at least 1 hour in a climate-controlledenvironment at 23 degrees Celsius with 50% humidity. The weight of thearticle is measured before and after the wash/dry/rest treatment, andthose weights are compared, and the percentage weight increase of thearticle after the wash/dry/rest treatment, if any, can be used todetermine the hydrophobicity in terms of water uptake. A value of about5% or less in the water uptake test described above typicallycorresponds to the upper threshold at which people will describe anarticle as feeling dry to the touch. The viscoelastic foams used for thesleeve 14 and the tiller material 34 of the pillow 10 may exhibit awater uptake between about 0% and about 5%, in some embodiments betweenabout 1% and about 5%, and in some embodiments between about 1% andabout 3%. The viscoelastic foams used for the sleeve 14 and the fillermaterial 34 of the pillow 10 may exhibit a water uptake of less thanabout 5%, in some embodiments less than about 4%, and in someembodiments less than about 3%. The remaining water present in theviscoelastic foams immediately following the water uptake test mayevaporate during subsequent use.

The viscoelastic foams used for the sleeve 14 and filler material 34 mayhave relatively large and open cells within the foam matrix, whichfacilitates drying. In other words, the cells of the viscoelastic foammay be essentially skeletal structures in which many (if notsubstantially all) of the cell walls separating one cell from another donot exist—the cells are defined by a plurality of supports or “window”and by no cell walls, substantially no cell walls, or by a substantiallyreduced number of cell walls. In some embodiments, the cells may besubstantially round and uniform in size and shape. Cell size may bemeasured using various methods familiar to those of ordinary skill inthe art; for example, cell size may be measured using Porescanequipment. The foams used for the sleeve 14 and filler material 34 ofthe pillow 10 may have an average cell size (in vertical and/orhorizontal diameter) between about 0.16 mm and about 0.19 mm, and insome embodiments between about 0.17 mm and about 0.19 mm, and in otherembodiments between about 0.17 and about 0.18 mm. In other words, thefoams used for the sleeve 14 and filler material 34 of the pillow 10 mayhave an average cell density between about 50 and about 65 cells/cm, andin some embodiments between about 52 and about 63 cells/cm, and in otherembodiments between about 59 and about 62 cells/cm. In addition, theviscoelastic foams used for the sleeve 14 and filler material 34 mayexhibit high air permeability, which also speeds and improves drying.Air permeability may be measured using various methods known to those ofordinary skill in the art, for example, according to ASTM D3574 or ENISO 7231, using test samples with a size of 38 cm² or 25 cm at aconstant pressure of 125 Pa. When tested with a sample size of 38 cm²under 125 Pa constant pressure, the viscoelastic foams of the sleeve 14and the filler material 34 of the pillow 10 may have air permeability ofat least about 1.0 liters per second (L/s), at least about 2.0 L/s, atleast about 3.0 L/s, or at least about 4.0 L/s. The viscoelastic foamsof the sleeve 14 and the filler material 34 of the pillow 10 may haveair permeability between about 1.0 L/s and about 5.0 L/s, in otherembodiments between about 2.0 and about 5.0 L/s, and in still otherembodiments between about 2.0 and about 4.0 L/s.

Suitable viscoelastic foams for the sleeve 14 and filler material 34 maybe produced, for example, using a process that comprises polyisocyanateand polymeric compounds having isocyanate-reactive groups. For example,such viscoelastic foams can be made in accordance with methods disclosedin U.S. Patent Application Publication No. 2013/0150476, the entirecontents of which are hereby incorporated by reference. Some embodimentsmay comprise a chain-extending or crosslinking agent, a compound havingone isocyanate-reactive group, a catalyst, or a blowing agent, or anycombination of the foregoing.

Useful polyisocyanates include in principle any known compounds havingtwo or more isocyanate groups in the molecule, alone or in combination.Diisocyanates are preferable. The process preferably usesdiphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), orMDI-TDI mixtures. The diphenylmethane diisocyanate used can be monomericdiphenyl diisocyanate selected from the group consisting of2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate or4,4′-diphenylmethane diisocyanate, or mixtures of two or all threeisomers, and also mixtures of one or more monomeric diphenylmethanediisocyanates with higher-nuclear homologs of diphenylmethanediisocyanate. The viscosity of diphenylmethane diisocyanate at 20degrees Celsius is preferably less than 200 mPas, more preferably lessthan 150 mPas and more preferably less than 100 mPas. It is particularlypreferable for the proportion of 2,2′-diphenylmethane diisocyanate to beless than 5 wt %, based on the total weight of polyisocyanates.

When TDI is used, it will usually be mixtures of the 2,4- and the2,6-isomer which are used. Commercially available mixtures with 80% 2,4and 60% 2,6 TDI and 35% 2,4 and 35% 2,6 TDI are particularly preferable.

In place of pure isocyanates or blended with these, so-called modifiedisocyanates can be used. These modified isocyanates may be formed forexample through incorporation of groups into the polyisocyanates.Examples of such groups are urethane, allophanate, carbodiimide,uretoneimine, isocyanurate, urea and biuret groups.

Particular preference is given to polyisocyanates modified with urethanegroups, these polyisocyanates being typically prepared by reacting theisocyanates with a deficiency of compounds having two or moreisocyanate-reactive hydrogen atoms. Compounds formed therefrom arefrequently referred to as NCO prepolymers, The compounds used and havingtwo or more isocyanate-reactive hydrogen atoms are preferably polymericcompounds having isocyanate-reactive groups and/or chain-extendingand/or crosslinking agents. Particular preference is likewise given tocarbodiimide- or uretoneimine-containing polyisocyanates, which areformed by specific catalyzed reaction of isocyanates with themselves.Mixtures of TDI and MDI can also be used.

Polymeric compounds having isocyanate-reactive groups have an averagemolecular weight of at least 450 g/mol and more preferably in the rangefrom 460 to 12,000 g/mol, and have two or more isocyanate-reactivehydrogen atoms per molecule. Polymeric compounds havingisocyanate-reactive groups preferably include polyester alcohols and/orpolyether alcohols having a functionality of 2 to 8, especially of 2 to6 and preferably 2 to 4 and an average equivalent molecular weight inthe range from 400 to 3000 g/mol and preferably in the range from 1000to 2500 g/mol. In some embodiments, polyether alcohols are used.

Polyether alcohols are obtainable by known methods, usually viacatalytic addition of alkylene oxides, especially ethylene oxide and/orpropylene oxide, onto H-functional starter substances, or viacondensation of tetrahydrofuran. When alkylene oxides are used, theproducts are also known as polyalkylene oxide polyols. UsefulH-functional starter substances include especially polyfunctionalalcohols and/or amines. Preference is given to using water, dihydricalcohols, for example ethylene glycol, propylene glycol, or butanedials, trihydric alcohols, for example glycerol or trimethylolpropane,and also more highly hydric alcohols, such as pentaerythritol, sugaralcohols, for example sucrose, glucose or sorbitol. Preferable aminesare aliphatic amines having up to 10 carbon atoms, for exampleethylenediamine, diethylenetriamine, propylenediamine, and also aminoalcohols, such as ethanolamine or diethanolamine. The alkylene oxidesused are preferably ethylene oxide and/or propylene oxide, whilepolyether alcohols used for preparing flexible polyurethane foamsfrequently have an ethylene oxide block added at the chain end. Usefulcatalysts for the addition reaction of alkylene oxides includeespecially basic compounds in that potassium hydroxide is industriallyhighly important. When the level of unsaturated constituents in thepolyether alcohols is to be low, di- or multi-metal cyanide compounds,so-called DMC catalysts, can also be used as catalysts. Viscoelasticflexible polyurethane foams can be produced using especially two- and/orthree-functional polyalkylene oxide polyols.

Useful compounds having two or more active hydrogen atoms furtherinclude polyester polyols obtainable for example from organicdicarboxylic acids having 2 to 12 carbon atoms, preferably aliphaticdicarboxylic acids having 8 to 12 carbon atoms, and polyhydric alcohols,preferably dials, having 2 to 12 carbon atoms and preferably 2 to 6carbon atoms. Useful dicarboxylic acids include for example succinicacid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacicacid, decanedicarboxylic acid, maleic acid, lunatic acid, phthalic acid,isophthalic acid, terephthalic acid and the isomeric naphthalenedicarboxylic acids. Use of adipic acid is preferable. The dicarboxylicacids can be used not only individually but also mixed with one another.Instead of the free dicarboxylic acids, it is also possible to use thecorresponding dicarboxylic acid derivatives, for example dicarboxylicesters of alcohols having 1 to 4 carbon atoms or dicarboxylicanhydrides.

Examples of alcohols having two or more hydroxyl groups and especiallydiols are: ethanediol, diethylene glycol, 1,2-propanediol,1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol,1,6-hexanediol, 1,10-decanediol, glycerol and trimethylolpropane.Preference is given to using ethanediol, diethylene glycol,1,4-butanediol, 1,5-pentanediol, hexanediol or mixtures of two or morethereof, especially mixtures of 1,4-butanediol, 1,5-pentanediol and1,6-hexanediol. It is further possible to use polyester polyols formedfrom lactones, e.g., ε-caprolactone, or hydroxy carboxylic acids, e.g.,ω-hydroxycaproic acid and hydroxybenzoic acids. The use of dipropyteneglycol is preferred.

The polymeric compounds having isocyanate-reactive groups comprise (1)10 to 40 wt % of at least one polyalkylene oxide having a hydroxylnumber of 90 to 300 mg KOH/g, based on a 3 to 6-functional startermolecule and a propylene oxide fraction, based on the alkylene oxidecontent, of 80 to 100 wt %, (2) 5 to 20 wt % of at least onepolyalkylene oxide having a hydroxyl number of 10 to 60 mg KOH/g, basedon a 2 to 4-functional starter molecule and a propylene oxide fraction,based on the alkylene oxide content, of 80 to 100 wt %, (3) 10 to 50 wt% of at least one polyalkylene oxide having a hydroxyl number of 10 to55 mg KOH/g, based on a 2 to 4-functional starter molecule and anethylene oxide fraction, based on the alkylene oxide content, of 70 to100 wt %, and (4) 0 to 20 wt %, preferably 1-20 wt % of at least onepolyalkylene oxide having a hydroxyl number of 50 to 200 mg KOH/g,preferably 56-200 mg KOH/g, based on a 2-functional starter molecule andan ethylene oxide fraction, based on the alkylene oxide content, of 80to 100 wt %, all based on the total weight of polymeric compounds havingisocyanate-reactive groups.

It is preferable to use exclusively polyether polyols as polymericcompounds having isocyanate-reactive groups. It is preferred that thepolymeric compounds having isocyanate-reactive groups comprise thepolyetherols (1) to (4) at not less than 80 wt %, preferably not lessthan 85 wt %, more preferably not less than 90 wt % and especially notless than 95 wt %, all based on the total weight of the polymercompounds having isocyanate-reactive groups. In some preferredembodiments, the polymeric compounds having isocyanate-reactive groups,in addition to the polyetherols (1) to (4) do not contain any furtherpolymeric compounds having isocyanate-reactive groups.

It is particularly preferable for the polyetherols, aside from thestarter, to include essentially exclusively ethylene oxide and propyleneoxide units. Here “essentially” is to be understood as meaning thatsmall amounts of other alkylene oxide units are not disadvantageous. Thefraction of alkylene oxide units other than ethylene oxide or propyleneoxide units is preferably less than 5 wt %, more preferably less than 1wt % and especially 0 wt %, all based on the total weight of alkyleneoxide units.

In some embodiments, the chain-extending agents and/or crosslinkingagents used are substances having a molecular weight of below 400 g/moland preferably in the range from 60 to 350 g/mol, chain extenders having2 isocyanate-reactive hydrogen atoms and crosslinkers having 3 or moreisocyanate-reactive hydrogen atoms. These can be used individually or inthe form of mixtures. Preference is given to using dials and/or triolshaving molecular weights less than 400, more preferably in the rangefrom 60 to 300 and especially in the range from 60 to 150. Possibilitiesare for example, aliphatic, cycloaliphatic and/or aromatic dials, andalso diols having aromatic structures, with 2 to 14 and preferably 2 to10 carbon atoms, such as ethylene glycol, 1,3-propanediol,1,10-decanediol, o-dihydroxycyclohexane, m-dihydroxycyclohexane,p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol andpreferably 1,4-butanediol, 1,6-hexanediol andbis(2-hydroxyethyl)hydroquinone, triols, such as1,2,4-trihydroxycyclohexane, 1,3,5-trihydroxycyclohexane, glycerol andtrimethylolpropane, and low, molecular weight hydroxyl-containingpolyalkylene oxides based on ethylene oxide and/or 1,2-propylene oxideand the aforementioned diols and/or trials as starter molecules.Particular preference for use as chain extenders is given tomonoethylene glycol, 1,4-butanediol and/or glycerol.

When chain-extending agents, crosslinking agents or mixtures thereof areused, the amounts in which they are used are advantageously in the rangefrom 0.1 to 20 wt %, preferably in the range from 0.5 to 10 wt % andespecially in the range from 0.8 to 5 wt %, based on the weight of thepolymeric compounds having isocyanate-reactive groups and thechain-extending agents.

In addition to polymeric compounds having isocyanate-reactive groups, itis optionally also possible to use one or more compounds having just oneisocyanate-reactive group. These compounds are for example monoamines,monothiols and/or monoalcohols, for example, based on polyethers,polyesters or polyether-polyesters. Monoalcohols used for example aremore preferably polyether monools obtained on the basis ofmonofunctional starter molecules, for example ethylene glycol monomethylether. These are obtainable similarly to the polyetherols describedabove via polymerization of alkylene oxide onto the starter molecule.Polyether monools preferably have a high proportion of primary OHgroups. It is particularly preferable to prepare polyether monools usingethylene oxide as sole alkylene oxide. Preferable monools furtherinclude compounds having an aromatic group. The number average molecularweight of compounds having one isocyanate-reactive group is preferablyin the range from 50 to 1000 g/mol, more preferably in the range from 80to 300 g/mol and especially in the range from 100 to 200 g/mol. Whencompounds having one isocyanate-reactive group are used, they arepreferably used in a proportion of 0.1 to 5 wt % and more preferably 0.5to 4.5 wt %, based on the total weight of polymeric compounds havingisocyanate-reactive groups and compounds having just oneisocyanate-reactive group.

Useful catalysts for preparing the viscoelastic polyurethane foams arepreferably compounds which greatly speed the reaction of thehydroxyl-containing components with the polyisocyanates and/or thereaction of isocyanates with water. Examples are amidines, such as2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines, such astriethylamine, tributylamine, dimethylbenzylamine, N-methylmorpholine,N-ethylmorpholine, N-cyclohexylmorpholine,N,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetramethylbutanediamine, N,N,N′,N′-tetramethylhexanediamine,pentamethyldiethylene-triamine, tetramethyldiaminoethyl ether,bis(dimethylaminopropyl)urea, dimethylpiperazine, 1,2-dimethylimidazole,1-azabicyclo-(3,3,0)-octane and preferably1,4-diazabicyclo-(2,2,2)-octane and alkanolamine compounds, such astriethanolamine, triisopropanolamine, N-methyl-diethanolamine,N-ethyldiethanolamine and dimethylethanolamine. Similarly suitable areorganic metal compounds, preferably organic tin compounds, such astin(II) salts of organic carboxylic acids, e.g., tin(II) acetate,tin(II) octoate, tin(II) ethylhexanoate and tin(II) laurate, and thedialkyltin(IV) salts of organic carboxylic acids, for example dibutyltindiacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltindiacetate, and also bismuth carboxylates, such as bismuth(III)neodecanoate, bismuth 2-ethylhexanoate and bismuth octanoate, ormixtures thereof. The organic metal compounds can be used alone orpreferably in combination with strong basic amines. When the polymericcompound having isocyanate-reactive groups is an ester, it is preferableto use exclusively amine catalysts.

Preference is given to using from 0.001 to 5 wt % and especially from0.05 to 2 wt % of catalyst or catalyst combination, based on the weightof the polymeric compound having isocyanate-reactive groups.

Polyurethane foams are further produced in the presence of one or moreblowing agents. By way of blowing agents, it is possible to usechemically acting blowing agent and/or physically acting compounds.Chemical blowing agents are compounds which react with isocyanate toform gaseous products, for example water or formic acid. Physicalblowing agents are compounds that have been dissolved or emulsified inthe reactants of polyurethane synthesis and vaporize under theconditions of polyurethane formation. Examples are hydrocarbons,halogenated hydrocarbons and other compounds, for example perfluorinatedalkanes, such as perfluorohexane, chlorofluorocarbons, and ethers,esters, ketones and/or acetals, for example (cyclo)aliphatichydrocarbons having 4 to 8 carbon atoms, hydrofluorocarbons, such asSolkanes® 365 mfc, or gases, such as carbon dioxide. In one preferableembodiment, the blowing agent used is a mixture of these blowing agents,comprising water and more preferably exclusively water.

The amount of physical blowing agents, if present, in a preferableembodiment is in the range between 1 and 20 wt % and especially 5 and 20wt %, and the amount of water is preferably in the range between 0.5 and8 wt % and more preferably between 0.8 and 6 wt % and especially between1 and 5 wt %, all based on the total weight of other components of thereaction.

Useful auxiliaries and/or addition agents may include for examplesurface-active substances, foam stabilizers, cell regulators, externaland internal release agents, fillers, pigments, dyes, flame retardants,antistats, hydrolysis control agents and also fungistats andbacteriostats.

To produce exemplary viscoelastic polyurethane foams for use in thedisclosed pillow 10, the polymeric compounds having isocyanate-reactivegroups, the optionally used chain-extending and/or crosslinking agents,the optionally used compounds having just one isocyanate-reactive groupwith a hydroxyl number of 100 to 500 mg KOH/g, the catalysts, theblowing agents, and also the optionally used auxiliaries and/or additionagents are typically mixed to form a so-called polyol component andreacted in that form with the polyisocyanates. The polyisocyanateprepolymers are reacted with the polyol component. The mixing ratios arechosen here such that the equivalence ratio of NCO groups ofpolyisocyanates to the sum total of reactive hydrogen atoms of compoundsthat make up the polyol component is preferably in the range from 0.65to 1.2:1, preferably in the range from 0.7 to 1.1:1 and especially inthe range from 0.1 to 1:1. A ratio of 1:1 here corresponds to anisocyanate index of 100.

The viscoelastic foams used for the sleeve 14 and filler material 34 arepreferably produced by the one-shot process, for example using ahigh-pressure or low-pressure technique. The foams can be obtainable inopen or closed metallic molds or via the continuous application of thereaction mixture to belt lines or in troughs to produce foam blocks.

It is particularly advantageous to proceed via the so-calledtwo-component process wherein, as mentioned above, a polyol component isproduced and foamed with polyisocyanate. The components are preferablymixed at a temperature in the range between 15 and 120 degrees Celsiusand preferably 20 to 80 degrees Celsius and introduced into the mold oronto the belt line. The temperature in the mold is usually in the rangebetween 15 and 120 degrees Celsius and preferably between 30 and 80degrees Celsius.

In some embodiments, the composition of the filler material 34 can bevaried to alter the characteristics of the pillow 10 and the cost of thepillow 10. For example, the filler material 34 may in some embodimentsbe a combination of granulated viscoelastic foam and a fiber material.The fiber material can be made from any kind of washable textile, suchas a natural textile (cotton) or a synthetic textile, which is oftenless expensive than viscoelastic foam. In some embodiments of thepresent invention, the fiber material has a density of about 1 g/cm³.However, a suitable density for the fiber material may be, for example,0.1-2 g/cm³. Further, a suitable density for the fiber material for asofter-feel pillow, for example, can be less than about 0.3 cm³.Likewise, a suitable density for the fiber material for a firmer-feelpillow, for example, can be greater than about 1.8 g/cm³. Alternatively,the fiber material used in combination with the granulated viscoelasticfoam as the filler material 34 can have any density in accordance withthe desired characteristics of the pillow 10.

In some embodiments of the invention, the filler material 34 comprisesabout 50% washable fiber or other material, while the remainingcomposition includes granulated viscoelastic foam, However, a suitablerange of fiber or other material in the filler material 34 for anaverage-cost pillow, for example, can be between about 20% and about80%. Further, a suitable range of fiber or other material in the tillermaterial 34 for a more expensive pillow, for example, can be more thanabout 30% of the filler material, Likewise, a suitable range of fiber orother material in the filler material 34 for a less expensive pillow,for example, can be greater than about 70% of the filler material.

In some embodiments of the present invention, the filler material 34 maybe a combination of granulated viscoelastic foam and polystyrene ballsor other polystyrene elements, which are often less expensive thanviscoelastic foam. The filler material 34 of this embodiment can alsoinclude a washable natural or synthetic fiber material depending on thedesired characteristics of the pillow. The polystyrene balls may consistof balls of a nominal diameter, or the polystyrene balls may consist ofballs of varying diameters. For example, the polystyrene balls may havea nominal diameter of about 5 mm. Also, the polystyrene balls mayconsist of varying diameters between about 1 mm and about 10 mm. Thepolystyrene balls can also be as small as 0.5 mm and as large as 20 mm,or the polystyrene balls can have other dimensions in accordance withthe desired characteristics of the pillow 10.

For example, in some embodiments of the invention, the filler material34 comprises about 50% polystyrene balls, while the remainingcomposition includes granulated viscoelastic foam. However, a suitablerange of polystyrene balls in the filler material 34 for an average-costpillow, for example, can be between about 20% and about 80%. Further, asuitable range of polystyrene balls in the filler material 34 for a moreexpensive pillow, for example, can be less than about 30% of the fillermaterial 34. Likewise, a suitable range of polystyrene balls in thetiller material 34 for a less expensive pillow, for example, can begreater than about 70% of the filler material 34.

When assembled, the pillow 10 can be washed and optionally subjected toa spin cycle in an ordinary household washing machine, and then tumbledried without damage such as cracked foam and opened seams or loss ofmechanical and viscoelastic properties. For example, the pillow 10should withstand washing temperatures of at least about 40 degreesCelsius, at least about 50 degrees Celsius, at least about 60 degreesCelsius, or at least about 70 degrees Celsius. The pillow may be tumbledried for about 0.5 hour, about 1 hour, about 1.5 hours, or about 2hours at high heat. In some embodiments, the pillow 10 may pass the ASTME2149 biocide test for at least about five, at least about seven, or atleast about 10 wash and dry cycles.

EXAMPLES

Example 1

Coverless pillows embodying the invention were subjected to 36 cycleswash/dry cycles, each including washing at 60 degrees Celsius withstandard washing detergent containing optical brightener and a 1600 rpmspin cycle followed by tumble drying at high heat for two hours, Thetest was conducted pursuant to BS EN ISO 6330:2001.

Results: Through the first 20 wash/dry cycles, an appearance assessmentrevealed pilling of netting, dimensional changes of up to −3.9% (length)and up to +2.6% (width), and slight yellowing of the sleeve attributableto detergent with optical brightener. Through wash/dry cycles 21-32, anappearance assessment revealed pilling of netting, dimensional changesof up to −4.6% (length) and up to +3.3% (width), slight yellowing of thesleeve attributable to detergent with optical brightener, and occasionalopening of stitching at sleeve corners. Through these wash cycles, nostitch opening was detected, nor breakdown of pattern quilting stitcheson the sleeve face, nor opening of sleeve seams to expose the fillermaterial, nor breaking of the viscoelastic foam in the sleeve.

Example 2

Water uptake of samples of viscoelastic foam was tested as follows.Samples were weighed and then washed in a household washing machine at awater temperature of 60 degrees Celsius. Following the wash step, thesamples were again weighed. The samples were then tumble dried for twohours in a household dryer, removed from the dryer, and allowed to restfor 24 hours in a climate-controlled room kept at constant 23 degreesCelsius and 50% relative humidity. Samples were weighed again followingthe rest period, and the values were used to calculate the water uptakefor each sample by dividing the weight gain observed after the restperiod by the original weight of the foam sample.

Weight Post- Weight Water Weight Pre- Weight Post- Drying and GainUptake Sample Wash (g) Wash (g) Rest (g) (g) (%) 1 1298.2 1369.8 1324.626.4 2.0 2 1283.4 1387.9 1330.7 47.3 3.7 3 1206.0 1271.4 1213.3 7.3 0.64 1194.7 1187.4 1193.5 −1.2 −0.1

Various features of the invention are set forth in the following claims.

What is claimed is:
 1. A washable pillow comprising: a sleeve defining acavity; and a filler material positioned within the cavity, wherein thefiller material includes a viscoelastic foam having a hydrophobicityexpressed in terms of water uptake between about 0% (w/w) and about 5%(w/w), an average cell size between about 0.16 mm and about 0.19 mm, andan air permeability between about 1.0 liters per second and about 5.0liters per second.
 2. The washable pillow of claim 1, wherein theviscoelastic foam has a hydrophobicity between about 1% (w/w) and about3% (w/w).
 3. The washable pillow of claim 1, wherein the viscoelasticfoam has an average cell size between about 0.17 mm and about 0.19 mm.4. The washable pillow of claim 1, wherein the viscoelastic foam has anair permeability between about 2.0 liters per second and about 4.0liters per second.
 5. The washable pillow of claim 1, wherein the sleeveincludes a first viscoelastic foam layer and a second viscoelastic foamlayer, and wherein the first and second viscoelastic foam layers areconnected together to form the cavity therebetween.
 6. The washablepillow of claim 5, wherein each of the first and second viscoelasticfoam layers has a hydrophobicity expressed in terms of water uptake ofless than about 5% (w/w), an average cell size between about 0.17 mm andabout 19 mm, and an air permeability of at least about 1.0 liters persecond.
 7. The washable pillow of claim 5, wherein each of the first andsecond viscoelastic foam layers has a thickness of about 10 cm.
 8. Thewashable pillow of claim 5, wherein the sleeve further includes a firstfabric layer covering an exterior surface of the first viscoelastic foamlayer and a second fabric layer covering an exterior surface of thesecond viscoelastic foam layer, and wherein the first and second fabriclayers are connected to the first and second viscoelastic foam layers,respectively.
 9. The washable pillow of claim 8, wherein the first andsecond fabric layers are stitched to the first and second viscoelasticfoam layers, respectively, along edges of each of the layers.
 10. Thewashable pillow of claim 9, wherein the sleeve further includes a firstnetting layer covering an interior surface of the first viscoelasticfoam layer and a second netting layer covering an interior surface ofthe second viscoelastic foam layer, and wherein the first and secondnetting layers are connected to the first and second viscoelastic foamlayers, respectively.
 11. The washable pillow of claim 10, wherein thefirst and second netting layers are stitched to the first and secondviscoelastic foam layers, respectively, along edges of each of thelayers.
 12. The washable pillow of claim 11, wherein the first fabriclayer, the first viscoelastic foam layer, and the first netting layerare quilted between the edges of the connected layers.
 13. The washablepillow of claim 12, wherein the second fabric layer, the secondviscoelastic foam layer, and the second netting layer are quiltedbetween the edges of the connected layers.
 14. The washable pillow ofclaim 1, wherein the viscoelastic foam is granulated.
 15. A washablepillow comprising: a sleeve including a first panel and a second panelconnected to the first panel along edges of the respective panels toform a cavity therebetween; a filler material positioned within thecavity, the filler material including a viscoelastic foam having ahydrophobicity expressed in terms of water uptake between about 0% (w/w)and about 5% (w/w); and stitching extending through each of the firstand second panels to define a quilting pattern between the edges of theconnected panels, wherein each of the first and second panels includes aviscoelastic foam layer, a netting layer adjacent an interior surface ofthe viscoelastic foam layer, and a fabric layer adjacent an exteriorsurface of the viscoelastic foam layer.
 16. The washable pillow of claim15, wherein the quilting pattern is on a face of each of the panels. 17.The washable pillow of claim 16, wherein the quilting pattern includeswaveforms having a wavelength of about 26 centimeters.
 18. The washablepillow of claim 17, wherein a maximum distance between adjacentwaveforms is about 12 centimeters, and wherein a minimum distancebetween adjacent waveforms is about 3 cm.
 19. The washable pillow ofclaim 15, wherein the netting layers of the first and second panels,respectively, are in facing relationship with the viscoelastic foamfiller material being disposed therebetween.
 20. The washable pillow ofclaim 15, wherein the viscoelastic foam is granulated.
 21. The washablepillow of claim 15, wherein the viscoelastic foam filler material andthe viscoelastic foam layers of the first and second panels,respectively, have a hydrophobicity between about 2% (w/w) and about 4%(w/w).
 22. The washable pillow of claim 15, wherein the viscoelasticfoam filler material and the viscoelastic foam layers of the first andsecond panels, respectively, have an average cell size between about0.16 mm and about 0.19 mm.
 23. The washable pillow of claim 22, whereinthe viscoelastic foam filler material and the viscoelastic foam layersof the first and second panels, respectively, have an average cell sizebetween about 0.17 mm and about 0.19 mm.
 24. The washable pillow ofclaim 15, wherein the viscoelastic foam filler material and theviscoelastic foam layers of the first and second panels, respectively,have an air permeability between about 1.0 liters per second and about5.0 liters per second.
 25. The washable pillow of claim 24, wherein theviscoelastic foam filler material and the viscoelastic foam layers ofthe first and second panels, respectively, have an air permeabilitybetween about 2.0 liters per second and about 5.0 liters per second.